A linear actuator driving device, such as a reciprocal motor, is a device also called “driver” which causes a moving element to reciprocate electrically by carrying out energization in response to a driving command. Regarding the linear actuator, such as a reciprocal motor, there is a case in which, in a non-energized state, the center of reciprocation of the moving element is displaced from the center of a predetermined movement possible range due to self weight and, therefore, the movable range becomes narrower than the original movement possible range. In this case, there is a problem that, in order to avoid collision with, for example, an unillustrated casing which houses the moving element and the stator, it is not possible to cause the moving element to reciprocate with amplitude that requires a range wider than the narrowed movable range.
As a means for solving this problem, Patent Document 1 discloses a device for electrically correcting offset displacement of a movable element by constantly carrying out offset energization: the disclosed device includes an offset correcting unit which corrects a driving command such that offset energization is carried out to cause the center of reciprocation of the moving element to move in a direction in which deviation between the center of reciprocation of the moving element and the center of a movement possible range is eliminated.
As another means for solving the above-described problem, Patent Documents 2 and 3 disclose devices for mechanically correcting offset displacement: in the disclosed devices, arrangement positions of permanent magnets are determined or strength of each permanent magnet is varied such that deviation is caused in magnetic fluxes of the permanent magnets in a non-energized state.